IgM anti-HAV antibodies indicate a recent infection with the hepatitis A virus. IgM anti-HAV antibodies can generally be detected in the blood as early as 2 weeks after the initial HAV infection. The antibodies will disappear from the blood 3 to 12 months after the infection. IgG anti-HAV antibodies indicate that you have had a hepatitis A viral infection. About 8 to 12 weeks after the initial infection with hepatitis A virus, IgG anti-HAV antibodies will appear and will remain in the blood for lifelong protection (immunity) against HAV.